In a rocky intertidal area of the pacific northwest, the removal of the keystone species (seastars) causes:

Answer;

Without the keystone species, the rocky inter-tidal ecosystem would be dramatically different or cease to exist altogether

Explanation;

Keystone species have low functional redundancy. This means that if the species were to disappear from the ecosystem, no other species would be able to fill its ecological niche.

For instance; the starfish Pisaster ochraceus is a keystone species in the rocky marine inter-tidal communities off the northwest coast of North America. It feeds on the mussel Mytilus californianus and is responsible for maintaining much of the local diversity of species within certain communities.

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